This invention relates to a method and an apparatus for preparing scrap metal charges for smelting furnaces.
As is known, in loading scrap metal into smelting furnaces it is common practice to either load the material loose, as piled up at the storing yards, or to first press the scrap metal into blocks and then load the blocks into the furnace.
While either methods have evident advantages of their own, especially in the instance of offcuts of a particular shape, if the optimum density of the charge in a furnace is considered, it must be recognized that neither of the cited prior methods is fully satisfactory, because the blocks, or "briquettes", tend to have too high a density, whilst the loose material has an excessively low density. In fact, the briquette density is not determined by the charge optimum, but rather by the requirement that the briquettes be in a stable state for handling, and if the pressing operations are carried out at a remote site from the furnace, then greater interest is attached to minimizing the specific volume.
There exists a chain of circumstances why the scrap metal is delivered loose to the steel works or smelting plants. It would be desirable here to press the metal scraps to a density more suitable to meet the furnace requirements. However, this would involve, as mentioned above, problems of material handling. It should be further noted that commercially available presses are designed to achieve the highest possible degree of compaction rather than adjustable densities.
Another drawback of the briquette forming method is that it is highly expensive. An accurate analysis of costs reveals that they are highly affected by the need for transporting the material from a loose state storing yard to a briquette storing area. This because the press output product does not yield a unit charge and must be cumulated, thus increasing the space and transport facility requirements.